insert unique data in a list

[knifenomad]

On 12월14일, 오후12시42분, Steven D'Aprano
<ste... at REMOVE.THIS.cybersource.com.au> wrote:
> On Sun, 13 Dec 2009 17:19:17 -0800, knifenomad wrote:
> > this makes the set type hashable.
>
> > class Set(set):
> >     __hash__ = lambda self: id(self)
>
> That's a *seriously* broken hash function.
>
> >>> key = "voila"
> >>> d = { Set(key): 1 }
> >>> d
>
> {Set(['i', 'a', 'l', 'o', 'v']): 1}>>> d[ Set(key) ]
>
> Traceback (most recent call last):
>   File "<stdin>", line 1, in <module>
> KeyError: Set(['i', 'a', 'l', 'o', 'v'])
>
> --
> Steven

of course it is broken as long as it uses it's instance id.
i added this to notify that unhashable can become hashable
implementing __hash__ inside the class. which probably set to None by
default.